Field of the Invention
The invention relates to a reconfigurable radio chip architecture and system, and in particular, without being limited hereby, to devices, methods, and related inventions of a network on a chip (NoC) multiple-input-multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) application specific integrated circuit (ASIC) which fully implements a 4×4 MIMO OFDM receiver and transmitter.
Background of the Invention
To support a wide range of throughputs over a variety of adverse conditions requires reconfigurability of the baseband processing of advanced radio communications systems. The system must reconfigure for trading off long range for throughput, or lower power versus throughput. Some communication links require adaptation to the presence of jammers or noise sources. Communication systems based on MIMO OFDM can be reconfigured to meet a wide variety of requirements for range and throughput. OFDM in particular has proven to be a robust system in the presence of multi-path fading, Doppler shift due to vehicle motion or variations in the channel. OFDM is also robust against system issues such as carrier offset between the transmitter and receiver, receiver phase noise offset and timing drift. With MIMO OFDM, the system can be trained to support multiple Modulation Coding Schemes (MCS) that tradeoff throughput for range and enhanced diversity.
It would be desirable to have a 4×2 MIMO OFDM system in which the transmitter has 4 transmit chains and the receiver has 2 receive chains which can be configured into a 2×2 system, a 4×1 system or even a 1×1 system depending in the throughput and power requirements. Depending on the communication environment, it would also be desirable to provide feedback between the base station and the subscribing station (for example between a rover and a fixed location lander) or low orbit satellite. In these cases, MIMO Beamforming would be desirable to achieve very high though-put at lower power or longer range compared to open loop MIMO systems.
Accordingly, there is a need for an architecture that can support both beamforming using Singular Value Decomposition (SVD) and at the same time space time coding and open loop MIMO systems. It is also desirable to support most of the advanced equalizers that are needed when dealing with not only adverse environments but also compatibility with other radio standards, and to provide a system that can be reconfigured for both closed loop beamforming and open loop MIMO systems.
A Reconfigurable Radio system must be able to support both high throughput and for power saving or long range, lower throughput. In the current IEEE 802.16e standard, scalable OFDMA is employed to support multiple rates but in a way to maintain robustness as the size of the FFT is increased to support higher throughput. The receiver chain of MIMO OFDM systems reveals areas for improvements to computational resources re-use, area optimization, and for reconfigurability for variable FFT sizes and MIMO configurations.